Bipolar electrolytic filter press cell frame

ABSTRACT

A cell frame for a bipolar electrolytic filter press cell includes an electrolysis-associated lower section and a gas disengagement or diverting upper section. A pressure bar extends across the cell frame immediately above the lower section to prevent distortion of the separator by cathode generated gases, and to promote disengagement of the gases. The frame, also, includes external headers in the upper section for collection of the gases evolved by the electrolysis of the electrolytic solutions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to electrolytic filter press cells. Moreparticularly, the present invention pertains to cell frames forelectrolytic filter press cells. Even more particularly, the presentinvention pertains to cell frames for bipolar electrolytic filter presscells.

2. Prior Art

As is known to those skilled in the art, a cell frame comprises thebasic repeat unit in an electrolytic filter press cell. The cell framefunctions as a separator or barrier between the anode of one cell andthe cathode of the adjacent cell. A linear series of cathodes, anodesand interposed cell frames constitutes a filter press cell, in toto.

The prior art is replete with a wealth of technology respecting filterpress cells. Generally, however, the prior art has paid a great deal ofattention to electrode construction, diaphragm materials and the like.On the other hand, little attention has been directed to the cell frameand means and methods for improving same.

In U.S. Pat. No. 3,836,448 there is disclosed a frame for a filter presscell which is divided into an upper zone and a lower zone. The upperzone is used to collect the gases evolved during the electrolyticprocess conducted in the lower zone. A plurality of apertures are formedin the frame structure to provide communication between the two zones.This reference, also, teaches the necessity of separate frames for thecathode and anode, as well as the need for the frames to be free ofelectrical insulating partitions. It is to be appreciated that the framestructure is complex in that separate frames for the anode and cathodemust be provided. Also, the need to be free of electrical insulatingpartitions requires separate structure therefor. This renders suchstructure expensive to manufacture.

Also, U.S. Pat. No. 3,252,883, teaches a cell frame for an electrolyticdiaphragm cell. The reference teaches laterally spaced outlets for thegases evolved during the electrolytic process. According to thisreference, however, the diaphragm must occupy substantially the entirespace within the frame. Thus, the frame cannot be utilized in anelectrolytic process which does not utilize a diaphragm or where thediaphragm does not occupy the entire space within the frame. Thisnegates any concept of a universally employable cell frame.

Other prior art background material can be found in U.S. Pat. Nos.3,856,652; 3,855,104; 2,522,681; 1,366,090 and 3,647,672.

The present invention, as will be appreciated from the detaileddescription thereof, provides a cell frame which is useful in amultiplicity of electrolytic processes and which includes means forprolonging the useful life thereof as well as facilitating theinstallation thereof.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a bipolarelectrolytic filter press cell frame having electrolyte feed and productremoval means associated with each electrolyte compartment.

In a first embodiment of the invention the lower section and uppersection are segregated by a pressure bar extending across the cellframe. The pressure bar obviates the potentiality of cathode-producedgases from distorting the separator or barrier material. The frame isadapted to be employed in a plurality of different electrolyticprocesses. The upper section is offset on the anode to increase thedepth of the anolyte compartment.

The present invention further includes improved means for sealing andhandling the frames hereof.

For a more complete understanding of the present invention reference ismade to the following detailed description and accompanying drawing. Inthe drawing like reference characters refer to like parts throughout theseveral views, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of an embodiment of an electrolyticfilter press cell frame in accordance with the present invention,

FIG. 2 is a perspective view of the electrolytic filter press cell frameof FIG. 1 with certain elements eliminated for purposes of clarity,

FIG. 3 is a cross-sectional view taken along line 3--3, and

FIG. 4 is a perspective view of the pressure bar.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawing and in particular, FIGS. 1 and 2, there isdepicted therein a bipolar electrolytic filter press cell frame,generally indicated at 10. The frame comprises a first or lower sectionor zone 12 and second or upper section or zone 14. The lower zone 12defines the electrode area where the electrolytic solution iselectrolyzed and the upper zone defines the means for collection ordisengagement of the gaseous products.

With more particularity, the cell frame 10 comprises an integral unitwhich is injection molded or likewise formed from any suitable syntheticresinous material, which is compatible with the electrolytes being used,such as filled or unfilled polypropylene.

The frame is molded such that there is provided a peripheral rim 16extending therearound and a recessed central web 18.

The area of the frame extending downwardly from the top of the web 18defines the lower zone of the frame.

As clearly shown in FIG. 3, the frame 10 is defined by the central web18 which is a substantially linear section 20. Integrally molded withthe section 20 is a U-shaped section 22 having legs 24, 26. The U-shapedsection 22 cooperates with the linear section 20 to define a recessedarea 28 between the legs 24, 26 on the anolyte side of the frame 10.Also, the leg 24 defines an upper barrier for the lower zone on thecathode side of the frame. By so constructing the frame a higher liquidlevel can be maintained on the anode side of the frame than the cathodeside.

The leg 26 has a plurality of ports 30 formed therethrough on the anodeside of the frame which communicate with external headers to permit gasdisengagement in a manner to be described subsequently.

The central web 18 is provided with a plurality of apertures 32. Theapertures 32 receive the bipolar connectors 34 therethrough which secureelectrodes 36, 38 to the central web. Although any bipolar connector canbe effectively used, herein, the central barrier 18 is configured toaccommodate the bipolar connector as described in U.S. Pat. No.3,788,966.

Also, it should be noted that the central barrier is recessed to createelectrolyte compartments behind the electrodes when used with a cellseparator 39, such as a membrane, diaphragm or the like, in a manner tobe described subsequently.

In order to prevent distortion of the cell separator caused by the gasesgenerated on the cathode side of the cell frame and to facilitatewithdrawal of the gases, the present invention further includes apressure bar 40 (FIG. 3). The pressure bar 40 extends across the widthof the central web 18 and is disposed on the anode side of the frame.The bar 40 is substantially co-planar with the anode associatedtherewith.

The pressure bar is formed from any suitable material, such as titaniumor the like. The pressure bar is secured to the frame 10 proximate thejunction between the section 20 and leg 24, by any suitable means, suchas threaded fasteners 42 or the like. The fasteners extend throughmetallic spacers 44 which maintain a pre-determined distance between theframe proper and the pressure bar. The space between the spacers permitsanolyte and anolyte-generated gases to rise to a level within the anodecompartment to allow the gases generated to escape through the ports 30.

The cell frame 10, further comprises a first pair of laterally spacedapart headers 46. The headers 46 are formed in the periphery of theframe 10 and are in communication with the ports 30, formed in leg 26 onthe anode side of the frame. The ports 30 extend between the top of therecess area 28 and transverse openings 48 in communication therewith.Means (not shown) are connected to the transverse openings 48 forwithdrawing the anode-generated gases at the end of the filter pressmodule.

The cell frame 10 further includes a second pair of opposed headers 50,connected with the cathode side of the frame. Withdrawal means (notshown) evacuated the cathode-generated gases from the headers 50 at theend of the filter press module. Because the catholyte is generallymaintained at a lower level in the lower zone than the anolyte level,the ports 52 open into communication with the lower zone at or near thetop of the linear section 20 or central web.

It is to be appreciated that the pairs of headers 46, 50 and the recesedarea or open interior 28 cooperate to define the upper zone 14 of theframe 10.

The present cell frame further includes means 56 for feeding theelectrolytic feed to the anode side of the frame 10. The means 56includes a transverse opening 58 and an internal bore 60 extendingbetween the transverse opening 58 and the anode side of the frame.

The means 56 is disposed at the lower zone of the frame and on oppositesides thereof.

Means 62 for withdrawing the catholyte solution is, also, provided inthe lower zone 12 and is formed in the peripheral rim. The means 62comprises a construction analogous to that of the means 56, but has aninternal bore 62 opening to the cathode side. In order to facilitate theforming of the instant frame each means 56 and 62 on each side of theframe is provided in a single header 64, 66, respectively.

The present frame further includes a pair of spaced apart bumpers 68,70. The bumpers are disposed on the bottom of the frame and areintegrally formed with the peripheral rim. The bumpers 68, 70 protectthe lower or bottom portion of the cell frame during the handlingthereof.

Mounted on each lateral side of the frame 10 are handles 72, 74. Eachhandle includes a shoulder 76, 78. The shoulder portion of the handlesseatingly engage and rest upon filter press frame supportsconventionally disposed within a filter press cell. The handles,preferably, are integrally formed with the peripheral rim of the frame.

Disposed on each lateral side or face of the frame is a pair oflaterally extending projections 80, 82, 84 and 86, respectively. Theprojections are disposed above and below the handles 72, 74, as shown.Preferably, the projections are integrally formed with the frame,proper. The projections have throughbores 88 extending therethrough.

The projections 80, 82, 84 and 86 support the protection rods (notshown) of the filter press module which extend through the bores 88. Asis known to those skilled in the art the protection rods are employed toprevent the possible opening of the press in the event of hydraulicclosure failure. The rod, also, holds the remaining frames together inthe event the press is broken and when removing a failing frame or cellseparator.

As shown in FIGS. 1 and 2, an aperture 90 is provided between thelaterally spaced apart headers 46. The aperture 90 is utilized to liftthe frame 10 during assembly of the filter press cell module.

Although not shown in the drawing, the frame 10 contemplates the sealingthereof with a gasketing secured to the frame about the peripherythereof. Separate gaskets can be deployed about the headers. Theperipheral gasketing is provided on both sides of the frame. It is to beappreciated that the peripheral gasketing eliminates internal leaks,since any leaks would occur at the outer edges of the frame. Thus, theleaks could be visually detected.

It is contemplated that in practicing the present invention, the centralweb 18 is devoid of any electrode support nubs or the like. Rather, theelectrodes 34, 36 comprise stiffened, segmented electrodes such asdescribed in copending U.S. patent application Ser. No. 535,321, filedDec. 23, 1974, and entitled "Self Supporting Electrodes for Chlor-AlkaliCell."

The present cell frame 10 is perfectly amenable in a bipolar diaphragmfilter press cell wherein the separator 39 is a diaphragm held in placeand sealed at the periphery of two adjacent frames in the module.

The separator 39 can comprise any suitable construction, such as apolymeric sheet diaphragm, deposited and fused synthetic fiberdiaphragm, ion exchange membrane or the like.

It is to be further appreciated that the present cell frame 10 is"universal" in that it is adaptable for a plurality of electrolyticprocesses including diaphragm cell processes and membrane cellprocesses, such as electro-organic synthesis.

For example, as a diaphragm cell for the production of chlorine andcaustic, brine is fed into the anolyte compartment through means 56.Chlorine is removed at the upper zone from the headers 46. By employinga chlorine back pressure there is a sufficient pressure differentialbetween the anolyte and catholyte compartments to cause hydraulic flowthrough the diaphragm. The week cell liquor is exhausted through themeans 60 via a perk-arm system. Hydrogen is exhausted through headers50.

As a membrane cell for the production of chlorine and caustic the brinefeed is introduced to the anolyte compartment through the means 56.Deionized or distilled water is entered into the catholyte compartmentvia means 62, if required. Chlorinated anolyte and chlorine gas areexhausted through the headers 46, and hydrogen gas and caustic areexhausted through headers 50.

The same frame is equally applicable to the production of sodiumdithionite and chlorine using either a membrane or a diaphragm as wellas electrochemical synthesis. This is because of the ability toindependently feed and/or exhaust the anolyte and catholytecompartments.

In using the present cell frame in a module for electroorganicsynthesis, a suitable separator 39 is utilized and the electrolytes areindependently fed to both electrode compartments.

The cell frame of the present invention provides utmost consideration tothe economics involved in electrolytic process by providing maximumproduction per unit floor space utilized. In a practicable embodimenthereof the frame has overall dimensions of about 2.0 × 1.36 meters witha thickness of 7.6 centimeters. Such dimensions permit the height of theelectrode compartment to be about 1.55 meters. However, smallerdimensions could be imparted to the frame hereof. In constructing afilter press module from about 20 to 50 of the instant frames aredeployed.

It should also be noted that even with the sizes accorded to presentframes the phenomenon of "gas blinding" can be eliminated. This would beachieved by pressurizing the gases above the liquid level in a mannerwell known.

Having thus described the invention what is claimed is:
 1. A cell framefor a bipolar electrolytic filter press cell, comprising:a. a peripheralrim, b. a first linear section defining a central web recessedlydisposed within the rim, one side of the web defining a catholyte sideand the other an anolyte side, c. a U-shaped section integrally formedwith the linear section and cooperating therewith to define a recessedarea communicating with the anolyte side above the first linear section,the recessed area extending away from the anolyte side of the centralweb, d. the portion of the frame extending from the top of the centralweb downwardly defining a lower zone at which electrolysis is carriedout, e. the portion of the frame extending upwardly from the top of thecentral web defining an upper zone for disengagement theelectrolysis-generated gases, and f. means for preventing distortion ofthe central web and facilitating disengagement of the gases disposedbetween the upper zone and the lower zone on the anolyte side of theframe.
 2. The cell frame of claim 1 which further comprises: at leastone header in communication with the recessed area and at least oneheader in communication with the cathode compartment, the headers andthe recessed area defining the upper zone.
 3. The cell frame of claim 2wherein the disengagement means comprises a pressure bar, disposed onthe anolyte side of the web and extending thereacross, the bar having aplurality of spacers disposed between the bar and the linear sectionsuch that the anolyte-generated gases rise therethrough into therecessed area.
 4. The cell frame of claim 2 which further comprises:apair of headers, one on each lateral side of the barrier, and formed inthe upper zone, the headers communicating with the anolyte side todisengage the gases therefrom.
 5. The cell frame claim 4 wherein thepair of anolyte associated headers are formed in the peripheral rim. 6.The cell frame of claim 1 which further comprises:a. a handle formed oneach lateral side of the frame, each handle seatingly engaging a filterpress frame support, b. at least one projection on each lateral side ofthe frame, the projections supporting the filter press protection rods,and c. means for facilitating the lifting of the frame formed at the topthereof in the rim.
 7. The cell frame of claim 1 which furthercomprises:a. means for feeding electrolyte solution to the anolyte sideof the barrier, the means being formed in the rim, b. means for feedingelectrolyte solution to the catholyte side of the barrier, the meansbeing formed in the rim, c. means for exhausting catholyte liquidproduct from the catholyte side of the barrier and being formed in therim, and d. means for exhausting anolyte liquid product from the anolyteside of the barrier and being formed in the rim, the means for feedingand the means for exhausting being disposed in the lower zone.
 8. In achlor-alkali bipolar electrolytic filter press cell frame having acentral web, a pressure bar therefor comprising:a. an elongated memberhaving a length substantially equal to the width of the web of the cellframe, and b. a plurality of spacers extending outwardly from theelongated member, the spacers maintaining a predetermined distancebetween the elongated member and the frame.
 9. The cell frame of claim 8which further comprises:means for fastening the elongated member to thecell frame.
 10. The cell frame of claim 9 wherein the means forfastening extend through the spacers.
 11. The cell frame of claim 8wherein the pressure bar is formed from titanium.
 12. In combinationwith a cell frame having a central web for a bipolar electrolytic filterpress cell, a pressure bar for preventing distortion of the frame andfor facilitating disengagement of the gases evolved in the cell, thepressure bar comprising:a. an elongated member having a lengthsubstantially equal to the width of the web of the cell frame, and b. aplurality of spacers extending outwardly from the elongated member, thespacers maintaining a pre-determined distance between the elongatedmember and the frame.
 13. The combination of claim 12 which furthercomprises:means for fastening the elongated member to the cell frame.14. The combination of claim 13 wherein the means for fastening extendsthrough the spacers.
 15. The pressure bar of claim 12 wherein thepressure bar is formed from titanium.